Electronic expansion valve

ABSTRACT

An electronic expansion valve includes a drive component including a screw rod which reciprocates axially and a nut which cooperates with the screw rod by screw threads, and a lower end of the screw rod forms the valve needle component. A sleeve is fixed in the main valve cavity, an upper portion of the sleeve cooperates with the nut, and a lower end of the sleeve is supported by the valve seat and surrounds the main valve port. The valve core seat is axially movably arranged in the sleeve, and the lower end of the screw rod extends into the sleeve to open and close the valve core valve port. The structural design of the electronic expansion valve prevents an excessive impact on a valve core seat caused by the refrigerant with high pressure when the refrigerant flows forward, thereby preventing the eccentricity of the valve core seat.

The present application is the national phase of InternationalApplication No. PCT/CN2012/079927, filed on Aug. 10, 2012, which claimsthe benefit of priority to Chinese Patent Application No. 201210146266.8titled “ELECTRONIC EXPANSION VALVE”, filed with the Chinese StateIntellectual Property Office on May 11, 2012, the entire contents ofwhich are incorporated herein by reference to the maximum extentallowable by law.

TECHNICAL FIELD

The present application relates to the technical field of fluid controlcomponents, and particularly to an electronic expansion valve.

BACKGROUND

In the air conditioner market, two electronic expansion valves areemployed since an indoor unit is disposed far away from an outdoor unitof an air conditioner. In addition, each of the two electronic expansionvalves is required to be connected to a respective one-way valve inparallel to improve the system efficiency to the greatest extent. Theschematic diagram of the system of the air conditioner is shown in FIG.1, and the working principle is briefly described as follows

The refrigerating operation is described as follows. Gaseous refrigerantwith high temperature and high pressure which is discharged from a gasdischarge pipe of a compressor 7′8 passes through, in turn, a connectingpipe D and a connecting pipe E of a four-way valve 7′1, an outdoor heatexchanger 7′2 (releasing heat by condensation), a first one-way valve7′4 (here, a first electronic expansion valve 7′3 does not function toregulate the flow), and a second electronic expansion valve 7′5 (here, asecond one-way valve 7′6 is closed, and the second electronic expansionvalve 7′5 functions to regulate the flow), and finally enters into anindoor heat exchanger 7′7 to be evaporated, so as to absorb heat torealize the refrigerating function. Here, the second electronicexpansion valve 7′6 is close to the indoor heat exchanger 7′7, thus theheat loss may be reduced (if the electronic expansion valve is too faraway from the evaporator, the liquid refrigerant with low temperatureand low pressure which is discharged from the electronic expansion valveis apt to be gasified, which not only causes heat loss, but also resultsin significant reduction of the utilization rate of the evaporator).Also, if the refrigerant with medium temperature and high pressure whichis discharged from the outdoor heat exchanger 7′2 passes through thefirst electronic expansion valve 7′3, a throttling effect may stilloccur even when the expansion valve is fully opened, which reduces thepressure of the refrigerant, and then when the refrigerant istransferred to the second electronic expansion valve 7′5, it is apt tobe gasified partly, therefore the throttling effect of the electronicexpansion valve is adversely affected, and the system efficiency isreduced.

The heating operation is described as follows. Gaseous refrigerant withhigh temperature and high pressure which is discharged from the gasdischarge pipe of the compressor 7′8 passes through, in turn, theconnecting pipe D and a connecting pipe C of the four-way valve 7′1, theindoor heat exchanger 7′7 (releasing heat by condensation), the secondone-way valve 7′6 (here, the second electronic expansion valve 7′5 doesnot function to regulate the flow), the first electronic expansion valve7′3 (here, the first one-way valve 7′4 is closed, and the firstelectronic expansion valve 7′3 functions to regulate the flow), andfinally enters into the outdoor heat exchanger 7′2 to be evaporated, soas to absorb heat to realize the refrigerating function. Here, the firstelectronic expansion valve 7′3 is close to the outdoor heat exchanger7′2, thus the heat loss may be reduced (if the electronic expansionvalve is too far away from the evaporator, the liquid refrigerant withlow temperature and low pressure which is discharged from the electronicexpansion valve is apt to be gasified, which not only causes heat loss,but also results in significant reduction of the utilization rate of theevaporator). Also, if the refrigerant with medium temperature and highpressure which is discharged from the indoor heat exchanger 7′7 passesthrough the second electronic expansion valve 7′5, the throttling effectmay still occur even when the expansion valve is fully opened, whichreduces the pressure of the refrigerant, and then when the refrigerantflows to the first electronic expansion valve 7′3, it is apt to begasified partly, therefore the throttling effect of the electronicexpansion valve is adversely affected, and the system efficiency isreduced.

However, in the current market, some customers require to integrate theone-way valve with the electronic expansion valve, so as to reduce thenumbers of parts and solder joints, and to further improve thereliability of the system.

In view of this, in the conventional technology, an electronic expansionvalve with function of a one-way valve is disclosed in Japanese PatentApplication Publication No. 2009-287913. Reference may be made to FIGS.2 and 3. FIG. 2 is a schematic view showing the structure of anelectronic expansion valve in the conventional technology which isperforming a flow regulation when the refrigerant flows forwards; andFIG. 3 is a schematic view showing the structure of the electronicexpansion valve in the conventional technology, wherein the electronicexpansion valve is opened when the refrigerant flows reversely.

As shown in FIGS. 2 and 3, the electronic expansion valve in theconventional technology includes a valve seat 1′. The valve seat 1′ isprovided with a main valve cavity 1′1, a transverse connecting port 1′2and a vertical connecting port 1′3, and an opening at an upper end ofthe vertical connecting port 1′3 forms a main valve port 1′31. A valvecore seat 2′ is provided inside the main valve cavity 1′1, and acircumferential side wall of the valve core seat 2′ abuts against aninner circumferential side wall of the main valve cavity 1′1, thus thevalve core seat 2′ is guided by the main valve cavity 1′1 and mayreciprocate along an axial direction of the main valve cavity 1′1, so asto open or close the main valve port 1′31. Further, as shown in FIGS. 2and 3, the valve core seat 2′ is provided with a secondary valve cavity2′1, and a valve core valve port 2′2 in communication with the secondaryvalve cavity 2′1, and a valve needle component 3′ extends into thesecondary valve cavity 2′1 and reciprocates along an axial direction ofthe secondary valve cavity 2′1, so as to open or close the calve corevalve port 2′2. Furthermore, as shown in FIGS. 2 and 3, thecircumferential side wall of the valve core seat 2′ is further providedwith a communicating hole 2′3 in communication with the secondary valvecavity 2′1, and the communicating hole 2′3 faces the transverseconnecting port 1′2, to allow the secondary valve cavity 2′1 tocommunicate with the transverse connecting port 1′2.

In addition, as shown in FIGS. 2 and 3, the transverse connecting port1′2 is connected to a transverse connecting pipe 4′1, and the verticalconnecting port 1′3 is connected to a vertical connecting pipe 4′2. Theflow of the refrigerant fluid from the transverse connecting pipe 4′1 tothe vertical connecting pipe 4′2 (i.e., a side of the transverseconnecting port 1′2 is a high pressure zone, and a side of the verticalconnecting port 1′3 is a low pressure zone) is defined as a forwardflow, and the flow of the refrigerant fluid from the vertical connectingpipe 1′3 to the transverse connecting pipe 1′2 (i.e., the side of thevertical connecting port 1′3 is a high pressure zone, and the side ofthe transverse connecting port 1′2 is a low pressure zone) is defined asa reverse flow. The valve needle component 3′ is connected to a screwrod 5′1, and the screw rod 5′1 cooperates with a nut 5′2 by screwthreads. In such structure, a magnet 6′2 is rotated under the action ofa magnetic field of a coil 6′1; and then the screw rod 5′1 is rotatedand axially reciprocates due to the screw-thread fit with the nut 5′2,thereby driving the valve needle component 3′ to reciprocate axially toopen and close the valve bore valve port 2′2.

As shown in FIG. 2, when the refrigerant flows forward, the side of thetransverse connecting port 1′2 is the high pressure zone, and the sideof the vertical connecting port 1′3 is the low pressure zone. The valvecore seat 2′ moves downward under the action of a pressure difference ofthe refrigerant, thereby closing the main valve port 1′31. On thisbasis, the refrigerant enters into the secondary valve cavity 2′1 fromthe transverse connecting port 1′2 through the communicating hole 2′3,the valve needle component 3′ opens the valve core valve port 2′2, andthe refrigerant entered into the secondary valve cavity 2′1 flows to thevertical connecting port 1′3 via the valve core valve port 2′2, and inturn flows into the vertical connecting pipe 4′2. In this operation, thescrew rod 5′1 moves axially to allow the valve needle component 3′ toregulate an opening of the valve core valve port 2′2, thereby achievingan object of flow regulation of the electronic expansion valve.

As shown in FIG. 3, when the refrigerant flows reversely, the side ofthe vertical connecting port 1′3 is the high pressure zone, and the sideof the transverse connecting port 1′2 is the low pressure zone. Here,the valve core seat 2′ is pushed to move upward under the action of thepressure difference of the refrigerant, thereby opening the main valveport 1′31. The refrigerant flows through the main valve port 1′31, themain valve cavity 1′1 and the transverse connecting port 1′2 to thetransverse connecting pipe 4′1, thereby achieving the function ofone-way communication of the one-way valve.

However, the above electronic expansion valve in the conventionaltechnology has the following defects.

As shown in FIG. 2, when the refrigerant flows forward, the side wall ofthe valve core seat 2′ faces the transverse connecting port 1′2, thusthe circumferential side wall of the valve core seat 2′ may be impactedby the refrigerant with high pressure. When the pressure of therefrigerant fluctuates, an eccentricity of the valve core seat 2′ may becaused, thus the valve core seat 2′ can not tightly seal the main valveport 1′31, which causes a large internal leakage, and adversely affectsthe working performance of the system. Furthermore, the eccentricity ofthe valve core seat 2′ may cause interference between the valve needlecomponent 3′ and the valve core valve port 2′2.

SUMMARY

The technical problem to be addressed by the present application is toprovide an electronic expansion valve. The structural design of theelectronic expansion valve may prevent an excessive impact on a valvecore seat caused by the refrigerant with high pressure when therefrigerant flows forward, thereby preventing the eccentricity of thevalve core seat, and avoiding an internal leakage, and ensuring thereliability of the operation of the system.

For solving the technical problem, an electronic expansion valve isprovided according to the present application, which includes a valveseat, a vertical connecting pipe and a transverse connecting pipe, thevalve seat is provided with a main valve cavity; the electronicexpansion valve further includes a main valve port in communication withthe vertical connecting pipe and a valve core seat configured to openand close the main valve port, the valve core seat is provided with avalve core valve port which allows a communication with the verticalconnecting pipe; and the electronic expansion valve further includes avalve needle component configured to open and close the valve core valveport, wherein,

the electronic expansion valve further includes a drive component, thedrive component includes a screw rod and a nut which cooperates with thescrew rod by screw threads, and a lower end of the screw rod forms thevalve needle component;

a sleeve is fixed in the main valve cavity, and an upper portion of thesleeve cooperates with the nut; the valve core seat is axially movablyarranged in the sleeve, and a lower portion of the screw rod extendsinto the sleeve to open and close the valve core valve port; and

a circumferential side wall of the sleeve is provided with a firstcommunicating hole close to the main valve port, the nut is providedwith a second communicating hole configured to allow the main valvecavity to communicate with a sleeve upper cavity; and in a case that afluid medium flows from the transverse connecting pipe to the verticalconnecting pipe, the valve core seat closes the main valve port, acommunication between the first communicating hole and the main valveport is disconnected, and meanwhile the sleeve upper cavity comes incommunication with the main valve cavity via the second communicatinghole; and in a case that the fluid medium flows from the verticalconnecting pipe to the transverse connecting pipe, the valve core seatmoves upward to open the main valve port, and the main valve port comesin communication with the main valve cavity via the first communicatinghole.

Preferably, a lower end of the sleeve is supported by the valve seat,and the lower end of the sleeve surrounds the main valve port.

Preferably, the valve seat is provided with a vertical connecting portfor mounting the vertical connecting pipe, and the lower end of thesleeve extends into the vertical connecting port and is supported by thevertical connecting port; and an inner wall of the lower end of thesleeve forms a main valve hole, and the main valve port is formed by anaperture at an upper portion of the main valve hole.

Preferably, a circumferential outer wall of a lower end of the valvecore seat forms a valve core seat sealing portion for opening andclosing the main valve port.

Preferably, an inner wall of the vertical connecting port is providedwith a connecting port stepped portion, an outer portion of the lowerend of the sleeve is provided with a first sleeve stepped portion, andthe first sleeve stepped portion is supported on the connecting portstepped portion.

Preferably, the outer portion of the lower end of the sleeve is furtherprovided with a second sleeve stepped portion, the vertical connectingpipe is sleeved on the lower end of the sleeve, and a top end surface ofthe vertical connecting pipe abuts against the second sleeve steppedportion.

Preferably, a valve core seat through hole is arranged axially in thevalve core seat, and an aperture at an upper end of the valve core seatthrough hole forms the valve core valve port.

Preferably, a lower portion of the nut is provided with a nut innerguide hole, and an upper portion of the sleeve is provided with a sleeveouter guide portion fitted in the nut inner guide hole; and

a lower end of the sleeve outer guide portion is provided with a thirdsleeve stepped portion, and a lower end surface of the nut is furthersupported on the third sleeve stepped portion.

Preferably, the third sleeve stepped portion extends downwardly in anaxial direction, and the first communicating hole is further provided onthe third sleeve stepped portion in a radial direction of the sleeve.

Preferably, a valve core seat guide hole, and a main valve hole havingan aperture at an upper end thereof to form the main valve port, arearranged coaxially inside the sleeve.

Preferably, the electronic expansion valve further includes a locatingplate fixedly provided in the main valve cavity, the locating plate isprovided with a non-circular profiled hole, and a circumferential outerwall of a lower portion of the nut is provided with a non-circularprofiled portion configured to cooperate with the non-circular profiledhole to prevent the nut from rotating.

Preferably, the locating plate is provided with a third communicatinghole, and the main valve cavity below the locating plate is incommunication with the second communicating hole through the thirdcommunicating hole.

Preferably, the circumferential outer wall of the lower portion of thenut is provided with a nut stepped portion, and an elastic component issleeved on the circumferential outer wall of the nut, and is elasticallycompressed between the locating plate and the nut stepped portion.

On basis of the conventional technology, the electronic expansion valveprovided by the present application further includes a drive component,the drive component includes a screw rod which reciprocates axially anda nut which cooperates with the screw rod by screw threads, and a lowerend of the screw rod forms the valve needle component;

a sleeve is fixed in the main valve cavity, an upper portion of thesleeve cooperates with the nut, and further, a lower end of the sleeveis supported by the valve seat, and the main valve port is surrounded bythe lower end of the sleeve; and the valve core seat is axially movablyarranged in the sleeve, and the lower end of the screw rod extends intothe sleeve to open and close the valve core valve port; and

a circumferential side wall of the sleeve is provided with a firstcommunicating hole close to the main valve port, and the nut is providedwith a second communicating hole configured to allow the main valvecavity to communicate with a sleeve upper cavity; and when the valvecore seat closes the main valve port, the communication between thefirst communicating hole and the main valve port is disconnected, andmeanwhile the sleeve upper cavity comes in communication with the mainvalve cavity via the second communicating hole; and when the valve coreseat opens the main valve port, and the main valve port comes incommunication with the main valve cavity via the first communicatinghole.

When the refrigerant flows forward, the side of the transverseconnecting pipe is a high pressure zone, and the side of the verticalconnecting pipe is a low pressure zone. The valve core seat movesdownward under the action of a pressure difference of the refrigerant toclose the main valve port. On this basis, the refrigerant enters intothe sleeve upper cavity via the second communicating hole, and when thevalve needle component opens the valve core valve port, the refrigerantin turn enters into the side of the vertical connecting pipe via thevalve core valve port. In this process, the valve needle component mayreciprocate axially with the screw rod, thereby regulating an opening ofthe valve core valve port, and achieving the object of flow regulationof the electronic expansion valve.

When the refrigerant flows reversely, the side of the verticalconnecting pipe is a high pressure zone, and the side of the transverseconnecting pipe is a low pressure zone. The valve core seat moves upwardunder the action of the pressure difference of the refrigerant, therebyopening the main valve port. The refrigerant passes through the mainvalve port, and then flows to the side of the transverse connecting pipevia the first communicating hole, thereby achieving the object ofone-way communication of a one-way valve.

In the above operation, when the refrigerant flows forward, the valvecore seat is arranged in the sleeve, and the sleeve is fixedly arrangedin the main valve cavity, thus the pressure impact on the valve coreseat from the high pressure refrigerant is largely borne by the sleeve,which significantly reduces the impact on the valve core seat, therebypreventing the eccentricity of the valve core seat, and avoiding aninternal leakage, and ensuring the reliability of the operation of thesystem. In addition, the refrigerant flows in through the secondcommunicating hole provided on the nut. The position of the nut ishigher than that of the valve core seat, thus the position of the secondcommunicating hole is higher than that of the valve core seat, i.e. therefrigerant flows in through the second communicating hole above thevalve core seat, thereby reducing the impact on the valve core seat fromthe refrigerant.

In summary, the electronic expansion valve according to the presentapplication may prevent an excessive impact on the valve core seatcaused by the refrigerant with high pressure, thereby preventing theeccentricity of the valve core seat, and avoiding an internal leakage,and ensuring the reliability of the operation of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the operating principle of an airconditioning refrigerating system in the conventional technology;

FIG. 2 is a schematic view showing the structure of an electronicexpansion valve in the conventional technology which is performing aflow regulation when the refrigerant flows forwards;

FIG. 3 is a schematic view showing the structure of the electronicexpansion valve in the conventional technology, wherein the electronicexpansion valve is opened when the refrigerant flows reversely;

FIG. 4 is a schematic view showing the structure of an electronicexpansion valve according to an embodiment of the present applicationwhich is performing a flow regulation when the refrigerant flowsforwards;

FIG. 5 is a schematic view showing the structure of the electronicexpansion valve in FIG. 4, wherein the electronic expansion valve isopened when the refrigerant flows reversely;

FIG. 6 is a schematic view showing the structure of a sleeve of theelectronic expansion valve in FIGS. 4 and 5;

FIG. 7 is a schematic view showing the structure of a valve core seat ofthe electronic expansion valve in FIGS. 4 and 5;

FIG. 8 is a partially enlarged view of portion A in FIG. 5;

FIG. 9 is a schematic view showing the structure of a nut of theelectronic expansion valve in FIGS. 4 and 5;

FIG. 9-1 is a sectional view of the nut in FIG. 9; and

FIG. 10 is a schematic view showing the structure of a locating plate ofthe electronic expansion valve in FIGS. 4 and 5.

Corresponding relationships between reference numerals and components inFIGS. 1 to 3 are as follows:

1′ valve seat, 1′1 main valve cavity, 1′2 transverse connecting port,1′3 vertical connecting port; 1′31 main valve port; 2′ valve core seat,2′1 secondary valve cavity, 2′2 valve core valve port, 2′3 communicatinghole; 3′ valve needle component; 4′1 transverse connecting pipe, 4′2vertical connecting pipe; 5′1 screw rod, 5′2 nut; 6′1 coil, 6′2 magnet;7′1 four-way valve, 7′2 outdoor heat exchanger, 7′3 first electronicexpansion 7′4 first one-way valve, valve, 7′5 second electronicexpansion 7′6 second one-way valve, valve, 7′7 indoor heat exchanger,and 7′8 compressor.

Corresponding relationships between reference numerals and components inFIGS. 4 to 10 are as follows:

1 valve seat, 11 main valve cavity, 12 transverse connecting port, 13vertical connecting port, 131 connecting port stepped 2 valve core seat,portion; 21 valve core valve port, 22 valve core seat sealing portion,23 valve core seat through 4 sleeve, hole; 41 first communicating hole,42 third sleeve stepped portion, 43 sleeve upper cavity, 44 main valvehole, 441 main valve port, 45 first sleeve stepped portion, 46 secondsleeve stepped 47 sleeve outer guide portion, portion, 48 valve coreseat guide hole, 51 vertical connecting pipe, 52 transverse connectingpipe; 61 screw rod, 611 valve needle component; 62 nut; 621 nut innerguide hole; 622 second communicating hole; 623 non-circular profiled 71magnet; portion; 8 locating plate; 81 non-circular profiled hole; 82third communicating hole; 9 elastic component. and

DETAILED DESCRIPTION

An object of the present application is to provide an electronicexpansion valve. The structural design of the electronic expansion valvemay prevent an excessive impact on a valve core seat caused by therefrigerant with high pressure when the refrigerant flows forward,thereby preventing the eccentricity of the valve core seat, and avoidingan internal leakage, and ensuring the reliability of the operation ofthe system.

For those skilled in the art to better understand technical solutions ofthe present application, the present application is described in detailin conjunction with drawings and embodiments hereinafter.

Reference is made to FIGS. 4 and 5. FIG. 4 is a schematic view showingthe structure of an electronic expansion valve according to anembodiment of the present application which is performing a flowregulation when the refrigerant flows forwards; and FIG. 5 is aschematic view showing the structure of the electronic expansion valvein FIG. 4, wherein the electronic expansion valve is opened when therefrigerant flows reversely.

In one embodiment, as shown in FIGS. 4 and 5, the electronic expansionvalve according to the present application includes a valve seat 1. Thevalve seat 1 is provided with a main valve cavity 11, a transverseconnecting port 12 and a vertical connecting port 13. A transverseconnecting pipe 52 is installed at the transverse connecting port 12,and a vertical connecting pipe 51 is installed at the verticalconnecting port 13. The electronic expansion valve further includes amain valve port 441 in communication with the vertical connecting pipe51, and a valve core seat 2 configured to open and close the main valveport 441. The valve core seat 2 is provided with a valve core valve port21 which allows a communication with the vertical connecting pipe 51.The electronic expansion valve further includes a valve needle component611 configured to open and close the valve core valve port 21.

On the basis of the above structure, as shown in FIGS. 4 and 5, theelectronic expansion valve further includes a drive component. The drivecomponent includes a screw rod 61 which reciprocates axially and a nut62 which cooperates with the screw rod 61 by screw threads, and a lowerend of the screw rod 61 forms the valve needle component 611. A sleeve 4is fixed in the main valve cavity 11, an upper portion of the sleeve 4cooperates with the nut 62, a lower end of the sleeve 4 is supported bythe valve seat 1, and the main valve port 441 is surrounded by the lowerend of the sleeve 4. The valve core seat 2 is axially movably arrangedin the sleeve 4, and the lower end of the screw rod 61 extends into thesleeve 4 to open and close the valve core valve port 21.

Further, as shown in FIGS. 4 and 5, a circumferential side wall of thesleeve 4 is provided with a first communicating hole 41 close to themain valve port 441, and the nut 62 is provided with a secondcommunicating hole 622 configured to allow the main valve cavity 11 tocommunicate with a sleeve upper cavity 43. When the fluid medium flowsfrom the transverse connecting pipe 52 to the vertical connecting pipe51, the valve core seat 2 closes the main valve port 441, and thecommunication between the first communicating hole 41 and the main valveport 441 is disconnected, and meanwhile the sleeve upper cavity 43 comesin communication with the main valve cavity 11 via the secondcommunicating hole 622. When the fluid medium flows from the verticalconnecting pipe 51 to the transverse connecting pipe 52, the valve coreseat 2 opens the main valve port 441, and the main valve port 441 comesin communication with the main valve cavity 11 via the firstcommunicating hole 41.

When the refrigerant flows forward, the side of the transverseconnecting pipe 52 is a high pressure zone, and the side of the verticalconnecting pipe 51 is a low pressure zone. The valve core seat 2 movesdownward under the action of a pressure difference of the refrigerant toclose the main valve port 441. On this basis, the refrigerant entersinto the sleeve upper cavity 43 via the second communicating hole 622,and when the valve needle component 611 opens the valve core valve port21, the refrigerant in turn enters into the side of the verticalconnecting pipe 51 via the valve core valve port 21. In this process,the valve needle component 611 may reciprocate axially with the screwrod 61, thereby regulating an opening of the valve core valve port 21,and achieving the object of flow regulation of the electronic expansionvalve.

When the refrigerant flows reversely, the side of the verticalconnecting pipe 51 is a high pressure zone, and the side of thetransverse connecting pipe 52 is a low pressure zone. The valve coreseat 2 moves upward under the action of the pressure difference of therefrigerant, thereby opening the main valve port 441. The refrigerantpasses through the main valve port 441, and then flows to the side ofthe transverse connecting pipe 52 via the first communicating hole 41,thereby achieving the object of one-way communication of a one-wayvalve.

In the above operation, when the refrigerant flows forward, the valvecore seat 2 is arranged in the sleeve 4, and the sleeve 4 is fixedlyarranged in the main valve cavity 11, thus the pressure impact on thevalve core seat 2 from the high pressure refrigerant is largely borne bythe sleeve 4, which significantly reduces the impact on the valve coreseat 2, thereby preventing the eccentricity of the valve core seat 2,and avoiding an internal leakage, and ensuring the reliability of theoperation of the system. In addition, the refrigerant flows in throughthe second communicating hole 622 provided on the nut 62. The positionof the nut 62 is higher than that of the valve core seat 2, thus theposition of the second communicating hole 622 is higher than that of thevalve core seat 2, i.e. the refrigerant flows in through the secondcommunicating hole 622 above the valve core seat 2, thereby reducing theimpact on the valve core seat 2 from the refrigerant.

Reference is made to FIGS. 6, 7 and 8. FIG. 6 is a schematic viewshowing the structure of the sleeve of the electronic expansion valve inFIGS. 4 and 5; FIG. 7 is a schematic view showing the structure of thevalve core seat of the electronic expansion valve in FIGS. 4 and 5; andFIG. 8 is a partially enlarged view of portion A in FIG. 5.

In the above technical solution, the manner for forming the main valveport 441 may be specifically designed. For example, as shown in FIGS. 4and 5, the lower end of the sleeve 4 extends into the verticalconnecting port 13, and is supported by the vertical connecting port 13.An inner wall of the lower end of the sleeve 4 forms a main valve hole44, and an aperture at an upper portion of the main valve hole 44 formsthe main valve port 441. In such structure, the main valve port 441 isformed on the inner wall of the sleeve 4, and compared to the structureof the main valve port 441 being arranged in the valve seat 1, suchstructure may facilitate ensuring the concentricity between the valvecore seat 2 in the sleeve 4 and the main valve port 441, therebyfacilitating improving the sealing performance.

Apparently, the manners for forming the main valve port 441 are notlimited in the present application, and as described above, any one offormation structures of the main valve port should be deemed to fallwithin the scope of the present application as long as the valve coreseat 2 movable in the sleeve 4 may close and open the main valve port.For example, the main valve port 441 may be formed by an aperture at anupper end of the vertical connecting port 13 as shown in FIGS. 2 and 3,and in such structure, the lower end of the sleeve 4 does not extendinto the vertical connecting port 13, but is supported on an inner wallof the valve seat 1 near the vertical connecting port 13, therefore thevalve core seat 2 movable in the sleeve 4 may still open and close themain valve port. Apparently, in such structure, in order to fix thesleeve 4 reliably, the inner wall of the valve seat 1 may be providedwith a mounting groove surrounding the main valve port, and the lowerend of the sleeve 4 may be fixed in the mounting groove.

In the above technical solution, as shown in FIG. 7, a circumferentialouter wall of the lower end of the valve core seat 2 forms a valve coreseat sealing portion 22 for opening and closing the main valve port 441.The valve core seat sealing portion 22 cooperates with the main valveport 441 in the sleeve 4 to realize the object of opening and closing.

In the above technical solution, a mounting structure between the lowerend of the sleeve 4 and the vertical connecting port 13 may bespecifically designed. For example, as shown in FIG. 8, the inner wallof the vertical connecting port 13 is provided with a connecting portstepped portion 131, an outer portion of the lower end of the sleeve 4is provided with a first sleeve stepped portion 45, and the first sleevestepped portion 45 is supported on the connecting port stepped portion131. This structural design expediently achieves the axial support forthe sleeve 4, and the reliability of this support is high.

Further, as shown in FIG. 8, the outer portion of the lower end of thesleeve 4 is further provided with a second sleeve stepped portion 46.The electronic expansion valve further includes a vertical connectingpipe 51, and the vertical connecting pipe 51 is sleeved on the lower endof the sleeve 4, and a top end surface of the vertical connecting pipe51 abuts against the second sleeve stepped portion 46. This structuraldesign expediently achieves installation and fixation between thevertical connecting port 13, the sleeve 4 and the vertical connectingpipe 51, and the reliability of this fixation is high.

In the above technical solution, as shown in FIG. 7, a valve core seatthrough hole 23 is arranged axially in the valve core seat 2, and anaperture at an upper end of the valve core seat through hole 23 formsthe valve core valve port 21. The valve needle component 3 cooperateswith the valve core valve port 21 to regulate the opening of the valvecore valve port 21, thereby achieving the object of flow regulation ofthe electronic expansion valve. Furthermore, in this structural design,the valve core seat through hole 23 in the valve core seat 2 may have alarge length, such as 5 mm, which allows the valve core seat 2 to be ina long cylindrical shape, thus the noise generated when the refrigerantpasses through the valve core seat 2 may be reduced.

In the above technical solution, specific designs may be made. Forexample, reference is made FIGS. 6, 9 and 9-1, wherein FIG. 9 is aschematic view showing the structure of the nut of the electronicexpansion valve in FIGS. 4 and 5; and FIG. 9-1 is a sectional view ofthe nut in FIG. 9.

As shown in FIG. 9-1, a lower portion of the nut is provided with a nutinner guide hole 621. As shown in FIG. 6, an upper portion of the sleeve4 is provided with a sleeve outer guide portion 47. As shown in FIGS. 4and 5, the sleeve outer guide portion 47 is fitted in the nut innerguide hole 621. Further, a lower end of the sleeve outer guide portion47 is provided with a third sleeve stepped portion 42, and a lower endsurface of the nut 62 is further supported on the third sleeve steppedportion 42.

In the above structure, due to the cooperation between the nut innerguide hole 621 and the sleeve outer guide portion 47, a betterconcentricity between the sleeve 4 and the nut 62 is ensured, which inturn ensures a better concentricity between the sleeve 4 and the screwrod 61. Apparently, in such structure, it is also possible to arrange ansleeve inner guide hole in the upper portion of the sleeve 4 and a nutouter guide portion at an outer portion of the lower end of the nut 62,and to fit the nut outer guide portion in the sleeve inner guide hole.

Further, as shown in FIG. 6, the third sleeve stepped portion 42 extendsdownwardly in the axial direction to the first sleeve stepped portion45, and the first communicating hole 41 is further provided on the thirdsleeve stepped portion 42 in a radial direction of the sleeve 4. Inother words, the circumferential side wall of the sleeve 4 is providedwith a circumferential protruding portion, a top wall of thecircumferential protruding portion forms the third sleeve steppedportion 42, and a bottom wall of the circumferential protruding portionforms the first sleeve stepped portion 45, and the first communicatinghole 41 is provided on the circumferential protruding portion.Apparently, such structural design not only facilitates forming the twosleeve stepped portions, but also facilitates providing the firstcommunicating hole 41, and such structure is simple and has a lowmanufacturing cost.

Moreover, as shown in FIG. 6, a valve core seat guide hole 48, and amain valve hole 44 having an aperture at an upper end thereof to formthe main valve port 441, are arranged coaxially inside the sleeve 4. Inthis structural design, the valve core seat guide hole 48 and the mainvalve hole 44 may be formed integrally, thereby ensuring a goodconcentricity therebetween. Meanwhile, the aperture at the upper end ofthe main valve hole 44 forms the main valve port 441, which ensures agood concentricity between the valve core seat 2 and the main valve port441. As shown in FIGS. 4 and 5, the valve core seat 2 is axially movablealong the valve core seat guide hole 48, thus a good concentricitybetween the valve core seat 2 and the main valve port 441 may beensured, which also improves a sealing performance of the valve coreseat sealing portion 22 for the main valve port 441, thereby preventingthe internal leakage.

In the above technical solutions, specific designs may be further made.For example, reference is made to FIGS. 4, 5, 9 and 10, wherein FIG. 10is a schematic view showing the structure of a locating plate of theelectronic expansion valve in FIGS. 4 and 5.

As shown in FIGS. 4 and 5, the electronic expansion valve furtherincludes a locating plate 8 fixedly arranged in the main valve cavity11. As shown in FIG. 10, the locating plate 8 is provided with anon-circular profiled hole 81. As shown in FIG. 9, a circumferentialouter wall of the lower portion of the nut 62 is provided with anon-circular profiled portion 623 configured to cooperate with thenon-circular profiled hole 81 to prevent the nut 62 from rotating. Dueto the cooperation between the non-circular profiled hole 81 and thenon-circular profiled portion 623, the rotation of the nut 62 may beprevented. It should be noted that, the non-circular profiled hole andthe non-circular profiled portion of any structures are deemed to fallin the scope of the present application, since the structure other thana circular hole and a circular portion may prevent the nut 62 fromrotating with respect to the locating plate 8, for example, thestructure may be triangular, quadrangular or polygonal.

Further, as shown in FIGS. 4, 5 and 10, the locating plate 8 is providedwith a third communicating hole 82, and the main valve cavity 11 belowthe locating plate 8 is in communication with the second communicatinghole 622 through the third communicating hole 82. In this structure,when the refrigerant flows forwards, the refrigerant flows through thethird communicating hole 82 and then flows into the second communicatinghole 622.

Furthermore, as shown in FIGS. 4 and 5, the circumferential outer wallof the lower portion of the nut 62 is provided with a nut steppedportion, and an elastic component 9 is sleeved on the circumferentialouter wall of the nut 62, and is elastically compressed between thelocating plate 8 and the nut stepped portion. Further, in the abovestructure, in order to reduce the processing difficulty of the nut 62,the second communicating hole 622 provided on the nut 62 is axiallyarranged as shown in FIG. 9.

In the present application, as shown in FIG. 4, in the state that therefrigerant flows forwards, the refrigerant flows from the transverseconnecting pipe 52 through the third communicating hole 82 on thelocating plate 8, the second communicating hole 622 on the nut 62, thesleeve upper cavity 43, and the valve core valve port 21 to the side ofthe vertical connecting pipe 51. The magnet 71, driven by the magneticfield of the coil, rotates and drives the screw rod 61 to rotate. Sincethe locating plate 8 restrains the nut 62 from rotating, and the elasticforce of the elastic component 9 and the sleeve 4 restrain the nut 62from axially moving, the screw rod 61 moves up and down by thescrew-thread fit with the nut 62, thereby opening and closing the valvecore valve port 21 by the valve needle component 611 formed by the lowerend of the screw rod 61. When the valve performs a full closingfunction, the screw rod 61 keeps rotating until the lower end thereof(i.e. the valve needle component 611) contacts the valve core valve port21, and at this time, the screw rod 61 cannot continue to movedownwardly. At this time, the magnet 71 and the screw rod 61 continuerotating, the thrust on the screw rod 61 from the valve core valve port2 is transferred to the nut 62 through the screw threads on the screwrod 61, and the nut 62 compresses the elastic component 9 to moveupwardly, thereby providing an open valve pulse for the product.

An electronic expansion valve according to the present application isdescribed in detail hereinbefore. The principle and the embodiments ofthe present application are illustrated herein by specific examples. Theabove description of examples is only intended to help the understandingof the method and idea of the present application. It should be notedthat, for the person skilled in the art, a few of modifications andimprovements may be made to the present application without departingfrom the principle of the present application, and these modificationsand improvements are also deemed to fall into the scope of the presentapplication defined by the claims.

The invention claimed is:
 1. An electronic expansion valve, comprising avalve seat, a vertical connecting pipe, and a transverse connectingpipe, the valve seat being provided with a main valve cavity; theelectronic expansion valve further comprising a main valve port incommunication with the vertical connecting pipe and a valve core seatconfigured to open and close the main valve port, the valve core seatbeing provided with a valve core valve port which allows a communicationwith the vertical connecting pipe; and the electronic expansion valvefurther comprising a valve needle component configured to open and closethe valve core valve port; wherein, the electronic expansion valvefurther comprises a drive component, the drive component comprises ascrew rod and a nut which cooperates with the screw rod by screwthreads, and a lower end of the screw rod forms the valve needlecomponent; a sleeve is fixed in the main valve cavity, and an upperportion of the sleeve cooperates with the nut; the valve core seat isaxially movably arranged in the sleeve, and a lower portion of the screwrod extends into the sleeve to open and close the valve core valve port;and a circumferential side wall of the sleeve is provided with a firstcommunicating hole close to the main valve port, the nut is providedwith a second communicating hole configured to allow the main valvecavity to communicate with a sleeve upper cavity; and in a case that afluid medium flows from the transverse connecting pipe to the verticalconnecting pipe, the valve core seat closes the main valve port, acommunication between the first communicating hole and the main valveport is disconnected, and meanwhile the sleeve upper cavity comes incommunication with the main valve cavity via the second communicatinghole; and in a case that the fluid medium flows from the verticalconnecting pipe to the transverse connecting pipe, the valve core seatmoves upward to open the main valve port, and the main valve port comesin communication with the main valve cavity via the first communicatinghole.
 2. The electronic expansion valve according to claim 1, wherein avalve core seat through hole is arranged axially in the valve core seat,and an aperture at an upper end of the valve core seat through holeforms the valve core valve port.
 3. The electronic expansion valveaccording to claim 1, wherein a lower portion of the nut is providedwith a nut inner guide hole and an upper portion of the sleeve isprovided with a sleeve outer guide portion fitted in the nut inner guidehole; and a lower end of the sleeve outer guide portion is provided witha third sleeve stepped portion, and a lower end surface of the nut isfurther supported on the third sleeve stepped portion.
 4. The electronicexpansion valve according to claim 3, wherein the third sleeve steppedportion extends downwardly in an axial direction, and the firstcommunicating hole is further provided on the third sleeve steppedportion in a radial direction of the sleeve.
 5. The electronic expansionvalve according to claim 3, wherein a valve core seat guide hole, and amain valve hole having an aperture at an upper end thereof to form themain valve port, are arranged coaxially inside the sleeve.
 6. Theelectronic expansion valve according to claim 1, wherein the electronicexpansion valve further comprises a locating plate fixedly provided inthe main valve cavity, the locating plate is provided with anon-circular profiled hole, and a circumferential outer wall of a lowerportion of the nut is provided with a non-circular profiled portionconfigured to cooperate with the non-circular profiled hole to preventthe nut from rotating.
 7. The electronic expansion valve according toclaim 6, wherein the locating plate is provided with a thirdcommunicating hole, and the main valve cavity below the locating plateis in communication with the second communicating hole through the thirdcommunicating hole.
 8. The electronic expansion valve according to claim6, wherein the circumferential outer wall of the lower portion of thenut is provided with a nut stepped portion, and an elastic component issleeved on the circumferential outer wall of the nut, and is elasticallycompressed between the locating plate and the nut stepped portion. 9.The electronic expansion valve according to claim 1, wherein a lower endof the sleeve is supported by the valve seat, and the lower end of thesleeve surrounds the main valve port.
 10. The electronic expansion valveaccording to claim 9, wherein a valve core seat through hole is arrangedaxially in the valve core seat, and an aperture at an upper end of thevalve core seat through hole forms the valve core valve port.
 11. Theelectronic expansion valve according to claim 9, wherein a lower portionof the nut is provided with a nut inner guide hole, and an upper portionof the sleeve is provided with a sleeve outer guide portion fitted inthe nut inner guide hole; and a lower end of the sleeve outer guideportion is provided with a third sleeve stepped portion, and a lower endsurface of the nut is further supported on the third sleeve steppedportion.
 12. The electronic expansion valve according to claim 11,wherein the third sleeve stepped portion extends downwardly in an axialdirection, and the first communicating hole is further provided on thethird sleeve stepped portion in a radial direction of the sleeve. 13.The electronic expansion valve according to claim 11, wherein a valvecore seat guide hole, and a main valve hole having an aperture at anupper end thereof to form the main valve port, are arranged coaxiallyinside the sleeve.
 14. The electronic expansion valve according to claim9, wherein the electronic expansion valve further comprises a locatingplate fixedly provided in the main valve cavity, the locating plate isprovided with a non-circular profiled hole, and a circumferential outerwall of a lower portion of the nut is provided with a non-circularprofiled portion configured to cooperate with the non-circular profiledhole to prevent the nut from rotating.
 15. The electronic expansionvalve according to claim 14, wherein the locating plate is provided witha third communicating hole, and the main valve cavity below the locatingplate is in communication with the second communicating hole through thethird communicating hole.
 16. The electronic expansion valve accordingto claim 14, wherein the circumferential outer wall of the lower portionof the nut is provided with a nut stepped portion, and an elasticcomponent is sleeved on the circumferential outer wall of the nut, andis elastically compressed between the locating plate and the nut steppedportion.
 17. The electronic expansion valve according to claim 9,wherein the valve seat is provided with a vertical connecting port formounting the vertical connecting pipe, and the lower end of the sleeveextends into the vertical connecting port and is supported by thevertical connecting port; and an inner wall of the lower end of thesleeve forms a main valve hole, and the main valve port is formed by anaperture at an upper portion of the main valve hole.
 18. The electronicexpansion valve according to claim 17, wherein a circumferential outerwall of a lower end of the valve core seat forms a valve core seatsealing portion for opening and closing the main valve port.
 19. Theelectronic expansion valve according to claim 17, wherein an inner wallof the vertical connecting port is provided with a connecting portstepped portion, an outer portion of the lower end of the sleeve isprovided with a first sleeve stepped portion, and the first sleevestepped portion is supported on the connecting port stepped portion. 20.The electronic expansion valve according to claim 19, wherein the outerportion of the lower end of the sleeve is further provided with a secondsleeve stepped portion, the vertical connecting pipe is sleeved on thelower end of the sleeve, and a top end surface of the verticalconnecting pipe abuts against the second sleeve stepped portion.